The present invention relates to a battery pack including a secondary battery.
As various types of motor-driven appliances, such as electric power tools or electric working machines, rechargeable motor-driven appliances are prevalent. For example, it may be configured such that a battery pack including a secondary battery is attached to an appliance main body, and thereby the appliance main body is operable by power from the battery pack.
A user of such a motor-driven appliance generally wants to work with a fully charged battery pack or an almost fully charged battery pack (with as large a remaining capacity as possible) attached so that the user can work as long as possible using the same single battery pack. Therefore, it is convenient for the user to be able to recognize a charge state of the battery pack.
Japanese Unexamined Patent Application Publication No. 2004-95299 discloses a technique in which a slidable sliding portion is provided in a side face of a battery pack. According to the technique, a user can easily determine, by means of the sliding portion, whether the battery pack is in a fully charged state or is already partially discharged.
Specifically, when the battery pack is inserted into a battery charger, the sliding portion slides and a position of the sliding portion is shifted to a “Fully Charged” position. Then, the position of the sliding portion is maintained at the “Fully Charged” position until the battery pack is inserted into a tool. When the battery pack is inserted into the tool, the sliding portion slides and the position of the sliding portion is shifted to a “Used” position. Thus, a user can easily determine a state of the battery pack depending on the position of the sliding portion.